TabHLH95-TaNF-YB1 module promotes grain starch synthesis in bread wheat

Area of Science:

• Plant Molecular Biology
• Agricultural Science
• Genetics

Background:

• Starch, the primary carbohydrate in wheat endosperm, is crucial for human energy.
• The transcriptional regulation of starch synthesis-related (SSR) genes in wheat remains largely uncharacterized.

Purpose of the Study:

• To investigate the role of the basic helix-loop-helix (bHLH) transcription factor TabHLH95 in regulating starch synthesis and grain development in wheat.

Main Methods:

• Analysis of TabHLH95 expression patterns in developing wheat grains.
• Characterization of Tabhlh95 knockout mutants and overexpression lines.
• Transcriptome analysis to identify downstream targets of TabHLH95.
• Promoter binding assays and interaction studies with TaNF-YB1.

Main Results:

• TabHLH95 is nucleus-localized and its knockout reduces grain size and starch content, while overexpression enhances them.
• TabHLH95 directly binds to and enhances the transcription of key SSR genes, including AGPL1, AGPL2, and ISA1.
• TabHLH95 forms a synergistic complex with TaNF-YB1 to regulate starch synthesis.

Conclusions:

• The TabHLH95-TaNF-YB1 complex positively regulates starch synthesis and grain weight by controlling SSR gene expression.
• TabHLH95 presents a promising target for genetic strategies aimed at improving wheat grain productivity.